Use a mountain bike to explore Anza-Borrego's Fish Creek Wash through Split Mountain and beyond

Anza-Borrego's Fish Creek Wash is the gateway to a fascinating labyrinth of rugged canyons, twisted arroyos, and mud hills covering the desiccated area known as the Carrizo Badlands. Why the name Fish Creek for a sand-filled desert wash devoid of water except after heavy rain? Apparently this was once a sluggish creek strewn with large potholes -- some containing desert pupfish -- worn into its bedrock floor. A huge flood in 1916, it is surmised, smothered the creekbed with a thick carpet of sand and destroyed the habitat for the fish.

Smoke tree, Fish Creek Wash

Today's Fish Creek supports only scattered smoke trees, desert lavender, mesquite, and other shrubs, plus a sporadic stream of travelers by foot, by jeep, and by bike. Over a distance of about 13 miles, the wash ascends some 1000 feet of elevation, a rather easy-going gradient for an out (uphill) and back (downhill) trek by means of riding a mountain bike. However, soft sand here and there may make the ride strenuous and a bit frustrating at times. Mud (after heavy rains) can make forward momentum a messy and glacially slow process, and that goes for motorized vehicles as well. Conditions are ideal when there's a little moisture on the ground from light rain, which may firm up the otherwise soft patches of sand.

To get to the starting point, drive east on Highway 78 to the desert town of Ocotillo Wells, then go eight miles south on the paved Split Mountain Road to the dirt-road turnoff for Fish Creek Primitive Camp. Depending on exactly where you park your car along Fish Creek Road, you may or may not require an Anza-Borrego Desert State Park $5-per-day parking pass; call 760-767-4205 or 760-767-5311 for more information. And, yes, you will need to bring along all the water you expect to drink.

At a point nearly two miles south of Split Mountain Road, the portals of Split Mountain loom on both sides. Here the waters of Fish Creek Wash (in rare flood stage, at least) have worn their way through a fault zone, creating sheer walls on both sides. Don't miss, on the right, just before the walls of Split Mountain begin to part, a spectacular anticline (an inverted U) of sandstone layers embedded in the canyon wall.

Next comes a landscape dominated by "mud hills" strewn with sparkling chips of gypsum crystal. Stick with riding on the main Fish Creek jeep route, and don't ride in areas not open to motor vehicles. Off-trail exploration is allowed in the state wilderness zones surrounding Fish Creek, but only on foot.

Work your way gradually upward -- if you have the mettle -- all the way to the confluence of Sandstone Canyon, some 13 miles from the pavement. The Fish Creek route continues north, but through less interesting terrain ahead, so this a good place to turn around and take advantage of a modest boost from gravity on the return leg.